Finding the Third Proportional to 394,491 and 640,912.50

Step by Step Solution

1. Step 1: Write the proportion equation
   394,491 : 640,912.50 = 640,912.50 : x
2. Step 2: Convert to fraction form
   394,491/640,912.50 = 640,912.50/x
3. Step 3: Cross multiply
   394,491x = 640,912.50 × 640,912.50
4. Step 4: Simplify right side
   394,491x = 410,768,832,656.25
5. Step 5: Solve for x
   x = 410,768,832,656.25/394,491
6. Step 6: Final answer
   x = 1,041,262.87